1. Field of the Invention
This invention relates to automatic parts handling apparatus, and more particularly to transfer assembly devices operable to invert a workpiece during its transfer between work stations.
2. Description of Prior Art
There is a need for improved assembly transfer apparatus which are capable of accurately picking up and placing workpieces at designated locations. Such apparatus are needed in manufacturing and assembly operations where workpieces are consecutively operated on at various work stations and must be transferred therebetween. Additionally, the workpieces may be required to be inverted or otherwise rotatably aligned during transfer between work stations. The use of such transfer devices is not new. Various prior art devices had such transfer capabilities but required primary and secondary transfer devices operating in tandem to complete a transfer. Still other devices required pre-programming of their control elements to achieve a continuous transfer activity, or were complex structurally, or even required auxiliary extending type pick-up units to complete their transfer and placing actions. Many prior art parts handler devices were slow in operation and incapable of the rapid mass movement of workpieces required in highly automated assembly operations. Other prior art devices utilized complicated linkage systems and exposed cam arrangements that had heavy and slow moving parts. Some prior art devices, where one shaft underwent both rotational and axially sliding movement to effect an arcuate transfer of a workpiece, had the undesirable problem of ineffective sealing about the rotating and sliding output shaft.
Examples of workpiece transfer devices, industrial robots and other mechanical manipulators typifying the prior art are: U.S. Pat. Nos. 2,904,192; 2,927,365; 2,997,186; 3,692,194; 3,951,271 and 4,113,115.